OBJECTIVE: The purpose of this study was to investigate the association between migraine headache and concussion in athletes. DESIGN: Case-control observational study. SETTING: A university-associated combined sports neurology and orthopedic sports medicine clinic. PARTICIPANTS: A total of 221 male (n = 140) and female (n = 81) athletes aged 12 to 24 years, including 115 concussion cases (52%) and 106 orthopedic controls (48%), were included in this study. INTERVENTIONS: Participants completed a one-page questionnaire that recorded their age, sex, reason for visit (concussion vs any other injury), concussion history, and self/immediate family member migraine headache history. MAIN OUTCOME MEASURES: The odds of having a previous history of migraine headache were compared in the concussion group versus orthopedic controls. RESULTS: Controlling for between-group differences in age and sex, there was a significant positive association between concussion group status and history of migraine headache [adjusted odds ratio (OR), 1.90; 95% confidence interval (CI), 1.03-3.50. P = 0.039]. However, when including a previous concussion history in the statistical model, this relationship failed to reach significance [adjusted OR, 1.68; 95% CI, 0.89-3.16. P = 0.107]. CONCLUSIONS: These results suggest that there is an association between migraine headache and concussion in athletes, but the cause-effect nature of this relationship cannot be determined. Migraine headache should be considered a modifying factor when caring for concussed athletes. Language: en